Determinação de cádmio e cromo em amostras lipídicas por espectrometria de obsorção atômica de alta resolução com fonte contínua e atomização em forno de grafite

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Química, 2016O presente trabalho trata sobre um método simples para a determinação de cádmio e cromo em amostras de óleo de peixe por espectrometria de absorção atômica de alta resolução e fonte continua em forno de grafite. As amostras foram preparadas pela diluição em 1-propanol. Foram utilizados tubos de grafite recobertos de platina e adição de paládio como modificador químico para a determinação de cádmio enquanto para a determinação de cromo não foi utilizado modificador químico permanente ou em solução. A exatidão do método foi avaliada pela comparação entre os resultados obtidos por digestão assistida em micro-ondas, apresentando resultados concordantes com este método alternativo de preparo de amostra. Além de amostras de óleo de peixe, foram quantificadas as concentrações de cádmio e cromo em outras matrizes lipídicas como manteiga de leite e manteiga de cacau. Para cádmio, os limites de detecção e quantificação foram de 0,5 pg e 1,5 pg, respectivamente, a faixa de trabalho foi de 1,5 a 330 pg de cádmio com um coeficiente linear de 0,998. Para cromo, os limites de detecção e quantificação para o método proposto foram de 7 pg e 23 pg, respectivamente; a faixa linear foi de 23 a 1080 pg de cromo, com um coeficiente linear de 0,999.Abstract: This work presents a simple method to determine cadmium and chromium in fish oil samples in graphite furnace by high-resolution continuum source atomic absorption spectrometry. The samples were prepared by dilution with 1-propanol. For cadmium determination a platinum coated graphite tube and palladium as chemical modifier were used. For chromium determination, no chemical permanent modifier or in solution was employed. The method was evaluated by the comparison with microwave-assisted digested samples, showing a good agreement with this alternative sample preparation. In addition, the concentrations of cadmium and chromium in butter and cocoa butter were measured. For cadmium, the limits of detection and quantification for the developed method were 0.5 pg and 1.5 pg respectively, the working range was 1.5 to 330 pg cadmium with a linear coefficient of 0.998. For chromium, the limits of detection and quantification for the developed method were 7 pg and 23 pg respectively, the working range was 23 to 1080 pg chromium with a linear coefficient of 0.999

Determination of arsenic in agricultural soil samples using High-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sample analysis

The authors are grateful to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support and scholarships. BW had a research scholarship from CNPq, Processo No. 303526/2016-5. The authors are also grateful to Analytik Jena for the donation of the HR-CS GF AAS Model contrAA 600 and for financial support.Peer reviewedPostprin

Investigation of chemical modifiers for the determination of cadmium and chromium in fish oil and lipoid matrices using HR-CS GF AAS and a simple ‘dilute-and-shoot’ approach

The authors are grateful to the Conselho Nacional de Desenvolvimento Científico and Tecnológico (CNPq), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support and scholarships. The present research was mostly financed through Project no. CNPq 406877/2013-0. The authors are also grateful to Analytik Jena for financial support and the donation of the contrAA 600.Peer reviewedPostprin

Development of a fast screening method for the direct determination of chlorinated persistent organic pollutants in fish oil by high-resolution continuum source graphite furnace molecular absorption spectrometry

The authors are grateful to the Conselho Nacional de Desenvolvimento Científico and Tecnológico (CNPq); the present research was mostly financed through Project no. CNPq 406877/2013-0. The authors are also grateful to the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support and scholarships, and to Analytik Jena for financial support and donation of the contrAA 600 high-resolution continuum source atomic absorption spectrometer.Peer reviewedPostprin

The use of high resolution graphite furnace molecular absorption spectrometry (HR -MAS) for total fluorine determination in extractable organofluorines (EOF)

Acknowledgment A.A. would like to thank the Ministry of Education and University of Jeddah in Saudi Arabia through the Cultural Bureau of Saudi Arabia, London for their financial support during the study period. A.O. wishes to thank the Royal Society of Chemistry Analytical Trust Fund for funding. M.S. would like to thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq for the financial support. L.S., J.B. and J.F. thank Formas for financial support (Grant number 2013–00794).Peer reviewedPostprin

Determinação de iodo por espectrometria de absorção molecular: um comparativo entre moléculas promissoras

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Química, 2020.Esta tese relata o uso de espectrômetros de absorção atômica de alta resolução com fonte contínua para a determinação de iodo através da espectrometria de absorção molecular. O presente trabalho conta com a revisão bibliográfica sobre técnicas clássicas e atuais para a determinação de iodo, a identificação das bandas de absorção de moléculas diatômicas de iodo realizada utilizando um espectrógrafo Echelle simultâneo molecular e também o estudo das melhores regiões espectrais para o monitoramento dessas moléculas utilizando um espectrômetro de absorção atômica de alta resolução com fonte contínua, com suas condições otimizadas para as moléculas CaI, SrI, BaI e InI. Dentre estas condições está o uso de irídio como modificador permanente para as moléculas CaI e SrI, o uso de platina para a molécula BaI e o uso de tungstênio para molécula InI. Para os modificadores selecionados, as temperaturas de pirólise/vaporização foram, respectivamente, de 1100 oC / 2400 oC para CaI, 1200 oC / 2200 oC para SrI, 1300 oC/ 2200 oC para BaI e 300 oC / 1300 oC para InI. Os métodos desenvolvidos foram aplicados em amostras de fármacos e suplementos, sendo que os limites de detecção absolutos para os métodos variaram entre 20 ng para a molécula SrI a 60 ng para a molécula BaI. Os métodos descritos foram validados, com base na RDC 166/2017 da ANVISA para validação de métodos para fármacos e medicamentos.Abstract: This thesis reports the use of high-resolution continuum source atomic absorption spectrometers for the determination of iodine via molecular absorption spectrometry. The present work includes a bibliographic review on classic and current techniques for the determination of iodine, the identification of the bands of absorption of diatomic molecules of iodine performed by molecular simultaneous Echelle spectrograph and also the study of the best spectral regions for the monitoring of these molecules using a high-resolution continuum source atomic spectrometer, with its conditions optimized for CaI, SrI, BaI and InI molecules. Among these conditions, is the use of iridium as a permanent modifier for the CaI and SrI molecules, the use of platinum for the BaI molecule and the use of tungsten for the InI molecule. For the selected permanent modifiers, the pyrolysis temperatures were, respectively, 1100 oC / 2400 oC for CaI, 1200 oC / 2200 oC for SrI, 1300 oC / 2200 oC for BaI and 300 oC / 1300 oC for InI. The developed methods were applied to drug and supplement samples, and the absolute limits of detection for the methods ranged from 20 ng to 60 ng. The described methods were validated, based on RDC 166/2017 of ANVISA legislation for method validation applied to drugs and medicines

What influences upland soil chemistry in the Amazon basin, Brazil? Major, minor and trace elements in the upper rhizosphere

Increasing land transformation in the Amazon basin, from forest to post-forest usage such as pastureland, agriculture and agroforestry, triggers significant changes in hydrology, soil fertility and regional climatology. However, relatively little is known about Amazon basin soil chemistry in general and about its possible alteration with recent land-use change. We present robust pedogeochemical data for 65 elements and oxides, and evidence for modification due to recent deforestation and post-forest land use on upland soils in Amazonas state, Brazil. Differences emerge in median element concentrations between these two land-cover types, and between central and southern parts of the basin. These new data, a product of the bi-national EcoRespira-Amazon (ERA) project, are based on triplicate sampling under different seasonal conditions at 29 sites, representing ca. 740,000 km2 and average annual meteorological conditions. Mineral soil samples (TOP: 0–20 cm; BOT: 30–50 cm) characterize the active upper rhizosphere. Data were obtained with very tight quality control from sampling to analysis (following GEMAS protocols), using various overlapping analytical methods. Some major, minor and trace element concentrations deviate strongly from established world soil averages, including the recent PEGS2.Geological (lithological) and weathering boundary conditions define the primary soil chemical signal. This is overprinted by biogeochemical forces (ecosystem feedbacks), and recently by human intervention (change of land cover, deforestation). The general assumption of depleted tropical soils is not justified as such – a more differentiated view is needed, since carbon and macronutrients such as nitrogen and phosphorous, albeit not always plant-available, do often occur in relatively high concentrations (median values TOP: 1.9, 0.15 and 0.02 wt%). Calcium, magnesium and potassium are truly depleted (median values TOP: 0.025, 0.095 and 0.065 wt%), albeit with noticeable variance. Trace elements, from silver to zirconium and including REE, show highly differentiated responses. Most are relatively enriched in post-forest soils; a subtle signal that is interpreted as reduced plant-soil interaction. BOT concentrations are generally higher than those in TOP soil, reflecting weathering conditions and biogeochemical cycling – with interesting exceptions (Br, Cd, Rb)211COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESNão te

What influences upland soil chemistry in the Amazon basin, Brazil? Major, minor and trace elements in the upper rhizosphere

Increasing land transformation in the Amazon basin, from forest to post-forest usage such as pastureland, agriculture and agroforestry, triggers significant changes in hydrology, soil fertility and regional climatology. However, relatively little is known about Amazon basin soil chemistry in general and about its possible alteration with recent land-use change. We present robust pedogeochemical data for 65 elements and oxides, and evidence for modification due to recent deforestation and post-forest land use on upland soils in Amazonas state, Brazil. Differences emerge in median element concentrations between these two land-cover types, and between central and southern parts of the basin. These new data, a product of the bi-national EcoRespira-Amazon (ERA) project, are based on triplicate sampling under different seasonal conditions at 29 sites, representing ca. 740,000 km2 and average annual meteorological conditions. Mineral soil samples (TOP: 0–20 cm; BOT: 30–50 cm) characterize the active upper rhizosphere. Data were obtained with very tight quality control from sampling to analysis (following GEMAS protocols), using various overlapping analytical methods. Some major, minor and trace element concentrations deviate strongly from established world soil averages, including the recent PEGS2. Geological (lithological) and weathering boundary conditions define the primary soil chemical signal. This is overprinted by biogeochemical forces (ecosystem feedbacks), and recently by human intervention (change of land cover, deforestation). The general assumption of depleted tropical soils is not justified as such – a more differentiated view is needed, since carbon and macronutrients such as nitrogen and phosphorous, albeit not always plant-available, do often occur in relatively high concentrations (median values TOP: 1.9, 0.15 and 0.02 wt%). Calcium, magnesium and potassium are truly depleted (median values TOP: 0.025, 0.095 and 0.065 wt%), albeit with noticeable variance. Trace elements, from silver to zirconium and including REE, show highly differentiated responses. Most are relatively enriched in post-forest soils; a subtle signal that is interpreted as reduced plant-soil interaction. BOT concentrations are generally higher than those in TOP soil, reflecting weathering conditions and biogeochemical cycling – with interesting exceptions (Br, Cd, Rb). © 2019 Elsevier B.V